The drama started at about 3.30pm yesterday when a man said he saw the woman, described as white and in her 30s or 40s, jump into the water from the river bank near Carrow Road.

He flagged down a passerby Paul Belton, who he saw using a mobile phone, and asked him to phone 999 while he used a nearby flotation ring to try to bring the woman closer to the river bank.

Mr Belton, 41, said some young men who had hired a boat were going past the scene and phoned the police at the same time.

He said the police arrived almost instantly, and added: “The policeman tried to lift the lady and he asked me to hold her head out of the water. We then all dragged her out and the policeman took over and another guy came and did CRP.”

River Wensum rescue. Photo: Josh Burgess

He said one policeman waded into the shallow water at the edge of the river, and it took three men to drag the woman out of the water.

He said police then screened off the scene while they continued to treat her on a patch of grass beside the river.

Mr Belton, who is from Morston on the north Norfolk coast, said he was only in the area so he could visit the football club to pay for his daughter’s football lessons, and it was lucky the woman was spotted before she drifted into a more secluded part of the Wensum.

He said: “It was all so quick. The adrenaline kicks in. It was a case of ‘she’s face down in the water; let’s get her out’. The emergency services were amazing. It was amazing what they can do.”

He said the woman was unconscious when she was taken out of the water.

Josh Burgess, 14, from Loddon, saw an air ambulance fly two low circuits over the scene, before landing near the football stadium, and described the atmosphere as “tense” as the emergency services worked hard to save the woman.

She was taken to the Norfolk and Norwich University Hospital by land ambulance and nearby roads, which had been closed to make room for the helicopter, reopened at 4.40pm.

Police said this morning the woman was in a serious but stable condition in hospital.